It depends on where you are and where they live.
For instance if I am driving on the highway and someone cuts me off I flash my lights to let them know how friggin close they came, but I don't "drive with my high beams".
If someone is tailgating me hard core I just slow down to tap the brake pedal with my left foot. I have no respect for people who tail gate. Now there is a DIFFERENCE. If someone pulls behind me after switching lanes and is on my bumper for 30 seconds thats not tail gating. When the guy is there for 5 minutes and he could see what station my radio is tuned too... then I get mad.
Throwing water bottles or apple cores and other random non-damaging objects works wonders. My brother uses ball-bearings, but he is on a bike and if your tailing him its extremely dangerous. Ball bearings shatter the front window and destroy rads.
IF HOWEVER **** HAPPENS ON THE SIDE ROADS NEAR MY HOUSE...
I follow them. I pulled off the Highway one time, it drop to a 30mph zone, so I slow to like 40, but this guy wants to do 80. At the stop sign I get the "whats your problem kid" and I tell the guy "Sorry sir, but I like to respect the speed limits". He tell me to **** off, and then I proceed to follow him from a distance. After he pulls into his driveway, he is almost at his front door, I stop infront of his house, and say... "Would you like me to show you how your suppose to stop at a stop sign too", and drive off.
The following day I deposited a "Driver's Handbook" inside his mail box.